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Biomedical subjects

M Griffiths

Publications and source records attributed to M Griffiths.

At least 73 records · Page 4Linked to original sources
PubMed1995

A microprocessor based photoplethysmograph for use in clinical practice.

A microprocessor-based system of photoplethysmography and its use in measuring skin blood flow is described. The system was designed specifically for use over long periods and for the analysis of the output to be handled by a personal computer. The photoplethysmograph described in this paper is shown to be a qualitative method for assessment of changes in peripheral skin blood flow. There is potential for use of this instrument in a variety of clinical conditions.

Adult↗
PubMed1995

Diurnal variation of sex hormone binding globulin and insulin-like growth factor binding protein-1 in women with polycystic ovary syndrome.

OBJECTIVES: The aim of this study was to examine (1) the diurnal variation in SHBG and (2) the inter-relationships of insulin, IGF-I, SHBG and IGFBP-1 over 24 hours in 10 women with anovulatory PCOS and compare them with weight-matched ovulatory controls. PATIENTS AND METHODS: The two groups comprised 10 anovulatory women with PCOS (as defined by clinical, ultrasound and biochemical criteria) and 10 weight matched controls. Serum samples were taken at two-hourly intervals for 24 hours and stored for measurement of SHBG, IGFBP-1, insulin and IGF-I. Differences between the groups were compared using the Wilcoxon ranked paired tests of the individual peak and trough concentrations in each group. The variation in insulin, IGFBP-1 and SHBG concentrations over 24 hours was tested using two-way analysis of variance with the factors time and subject. Spearman's correlation coefficient was calculated from the subjects' median value over 24 hours. RESULTS: The median (interquartile range) body mass index (BMI) was 25.2 (22.2-29.3) in the PCOS group and 24.3 (23.2-25.7) kg/m2 in the control group. Serum testosterone (T) and LH levels were significantly raised in the PCOS group compared to the control group; T 3.8 (2.9-5.6) vs 1.9 (1.9-2.5) nmol/l (P < 0.007) and LH 12 (10-15) vs 4.1 (3.6-4.5) IU/I (P < 0.005) respectively. There was no diurnal variation in SHBG. The median (interquartile ranges) of the peak SHBG concentrations was lower in the PCOS group: 29.4 (14.9-39.4) vs 52.1 (39.4-61) nmol/l in the control group (P < 0.01). The fasting levels of insulin at 0600 h (median (interquartile ranges)) were not significantly different between the groups; 6.6 (5.4-9.8) and 6.2 (1.9-7.6) mU/l, respectively, although the peak median concentrations were significantly different; PCOS 66.1 (50.9-129.2) vs 40 (36.1-74.2) mU/l (P < 0.05). Two-way analysis of variance showed a diurnal variation in insulin concentrations in the control group (P = 0.001) but not in the PCOS group (P = 0.1). The diurnal variation in IGFBP-1 was similar in the two groups but the peak median levels were lower in the women with PCOS 54.9 (22.3-79.2) vs 71.5 (60.5-99.3) micrograms/l (P < 0.03). The decline in IGFBP-1 concentrations correlated with the increase in insulin concentrations. The IGF-I concentrations were similar in the two groups. There was a significant negative correlation between SHBG and insulin (P < 0.05) and between insulin and IGFBP-1 (P < 0.01). CONCLUSION: This study demonstrates that there is no diurnal variation in SHBG concentrations and confirms the finding of a marked diurnal variation in the concentration of IGFBP-1. Women with PCOS who are anovulatory have an abnormal pattern of insulin secretion with an absence of diurnal variation compared to weight matched controls. This provides further evidence of the relative insulin resistance which is independent of weight found in women with anovulatory PCOS. The inverse correlations of insulin concentrations with SHBG and IGFBP-1 support the role of insulin as a possible regulator of the circulating levels of these binding proteins although the difference in the time course of their response makes it unlikely that they are co-regulated.

Circadian Rhythm↗
PubMed1995

Sexual knowledge interview schedule: reliability.

The Sexual Knowledge Interview Schedule (SKIS) is a 46-item interview schedule with an abuse scale and knowledge scale. The knowledge scale includes feelings, body parts identification, body parts function and general sexual knowledge. The reliability of the SKIS is reported. Internal consistency for scales/subscales ranges from 0.78 to 0.96. Inter-rater reliability was 95.3% agreement and test-retest reliability was 70.1%.

Adolescent↗
PubMed1994

Implicit memory.

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Anesthesia, General↗
PubMed1994

Warts in butchers.

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Disease Susceptibility↗
PubMed1994

Neocortical cholinergic activities differentiate Lewy body dementia from classical Alzheimer's disease.

Activity of the enzyme which synthesizes acetylcholine, choline acetyltransferase, was estimated in the neocortex of three series of control and demented cases. Clinically demented cases were divided into those with the classical neuropathological features of Alzheimer's disease (numerous neocortical plaques and tangles) and those with Lewy bodies in the brain stem and cortex (together with plaques and variable neurofibrillary pathology). In the Lewy body cases neocortical choline acetyltransferase was consistently lower than in the classical Alzheimer-type cases. Two of the Lewy body cases with extremely low cholinergic activity were responders in therapeutic trials of the cholinesterase inhibitor, tacrine, and the combined data suggest that cholinergic therapy may be particularly relevant to patients with Lewy body type dementia.

Alzheimer Disease↗
PubMed1994

Cardiac hypertrophy alters myocardial response to ischaemia and reperfusion in vivo.

The impact of cardiac hypertrophy on myocardial biochemical and physiological responses to ischaemia-reperfusion (I-R) was investigated in vivo. Hypertrophy was produced by aortic constriction (PH) or swimming training (TH). Open-chest rat hearts in PH, TH and a sedentary control group (SC) were subjected: (1) to ischaemia, by surgical occlusion of the main descending branch of the left coronary artery for 30 min; (2) to I-R, by releasing the occluded blood vessel for 15 min; or (3) to a sham operation. Ischaemia per se had little effect on heart oxidative and antioxidant status, or lipid peroxidation. However, I-R significantly decreased glutathione (GSH) content, increased glutathione disulfide (GSSG) content, and reduced GSH/GSSG ratio in the SC hearts. These alterations were associated with decreased activities of GSH peroxidase and GSSG reductase, and an increase in lipid peroxidation. Myocardial ATP, total adenine nucleotide content and energy charge in SC were significantly decreased after ischaemia, whereas levels of purine nucleotide derivatives, particularly adenosine, were elevated. No significant alteration of GSH status of adenine nucleotide metabolism occurred after ischaemia or I-R in hypertrophied hearts. In both PH and TH, glutathione content was significantly higher than in SC, whereas activities of GSH peroxidase and GSSG reductases were lower. TH rats maintained a higher heart rate (HR), peak systolic pressure, and energy charge during I-R. These data indicate that hypertrophied but well-functioned hearts may be more resistant to I-R induced disturbances of myocardial oxidative and antioxidant functions.

Adenine Nucleotides↗
PubMed1994

Protective wear and instrument sterilisation/disinfection in UK general dental practice.

The 18,000 United Kingdom general dental practitioners registered for National Health Service (NHS) practice were surveyed in July 1991 to assess their current use of protective gloves, eyewear and masks, and instrument sterilisation. Nearly 7,000 (6,588) valid responses were obtained immediately; of these, 70% of practitioners wore gloves routinely for clinical work, but only 14.5% donned new gloves for each patient. About 60% wore protective eyewear routinely or all the time but 12% never wore eye protection, and only 36% of practitioners used masks. Autoclaves or chemical solutions were the most popular methods to disinfect handpieces, but less than half the respondents stated that handpieces were sterilised or disinfected after each patient use. Most respondents (81%) routinely used autoclaves for sterilisation of other instruments. Although the response rate to the questionnaire was low, the results indicate that, despite the risks of, and publicity about, cross-infection, a substantial number of NHS dental practitioners may not adequately disinfect or sterilise their equipment between patients.

Attitude of Health Personnel↗
PubMed1994

IgG2 associated hypergammaglobulinaemia in some Nigerians with HIV infection.

Concentrations of immunoglobulins (IgA, IgG and IgM) were measured in Nigerians with (HIV) infection. Considerable elevations up to two-fold the reference values were observed for IgG and IgM in the patient group as a whole but elevations in IgA concentration were least marked albeit significantly different from the healthy subjects. Elevation of a particular isotype was not always concomitant with elevation of the other major classes in the same patient. Overall, these elevations were observed in both symptomatic and asymptomatic infected subjects. Further analysis of IgG hyperglobulinemia showed that increases in this major class may be due to increased IgG2 subclass concentrations. It is suggested that elevation of IgG2 subclass in Nigerians with HIV infection and not IgG1 or IgG3 may be due to genetic and environmental factors rather than variation in the strain of the virus.

Case-Control Studies↗